In old-fashioned uniform, line dance (3,4)

I believe the answer is:

pas seul

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'dance' is the definition.
(pas seul is a kind of dance)

'in old-fashioned uniform line' is the wordplay.
'in old-fashioned' becomes 'passe' (synonyms. I am not sure about the 'in' bit.).
'uniform' becomes 'u' (phonetic alphabet: alpha, bravo, charlie etc.).
'line' becomes 'l'.
'passe'+'u'+'l'='PAS SEUL'

Can you help me to learn more?

(Other definitions for pas seul that I've seen before include "dance movement" , "dance without partner" , "Ballet solo" .)

I've seen this clue in The Times.

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